Excavations at the LoDaisKa Site in the Denver, Colorado area — Background and Themes

y inches above the ground surface at this spot. A second stake was located on a north-south line from the first (using magnetic north) at the opposite end of the shelter. A horizontal line connecting these stakes at the level of the datum point was considered the baseline. The area of the rock shelter to be excavated was then laid out in one yard squares. Letters were assigned to the grid lines running east-west, and numbers to those running north-south. Each square was designated by the grid lines intersecting at its northeast corner. To facilitate exact measurement, a series of stakes was set up along the baseline at intervals of two yards. From locations on the stakes on the same horizontal plane as the datum point, lines were extended to corresponding pitons driven into the rear wall of the overhang. A second series of connecting lines formed a suspended grid of two yard squares.

A preliminary test trench one yard wide and four yards long, was dug in squares M6-9 to determine whether complete excavation was warranted. Subsequent yard square test pits were sunk at P 7-8 and K 8. It was hoped that these would indicate the nature of the geologic stratigraphy and at least suggest the range of cultural materials which might be expected. Since excavation seemed warranted, the entire area to be worked was cleared of the surface layer of manure.

As set forth in the description of the site, the recent floor sloped up toward the northwest (Fig. 8). Test excavations indicated that the basal layer was approximately horizontal in a north-south direction, but sloped gently up toward the west. There seemed to be no significant correlation between geologic stratigraphy (see below) and typology in any except the lowest layer, which had not yet been extensively investigated. Because the evidence was as yet so scanty, it was decided to excavate with reference to both the surface and the datum point. Each square was treated as a separate unit and, except where natural levels were apparent, excavation proceeded in four inch levels measured from the surface at the northeast corner. Each level was also correlated with the datum point.

Both typological provenience and the position of the basal layer indicated that the major portion of the deposit had been laid down horizontally. To test this hypothesis a careful watch was kept for fragmentary specimens, in the hope of finding corresponding pieces from separate locations. The relative positions of these would suggest the nature of the surface on which they were deposited. Ten such fragments found comprised five artifacts: three potsherds, one handstone and one fragmentary grinding slab. Though some occurred as much as twelve yards apart, each pair fell within the same vertical level. From this analysis it appeared that the occupation levels were in fact approximately horizontal.

Stepped excavation seemed advisable in view of the unconsolidated nature of the deposit (Fig. 5). Vertical exposures more than two feet high collapsed as soon as the lower portions became thoroughly dry. These conditions made stratigraphic columns or balks impractical in most instances. However, by the use of rip-rapping, it was possible to leave a reference balk one foot wide on the north side of line N 5-11.

All material recovered was sifted through quarter inch mesh screens. Since it was fairly loose and dry, most of the earth was removed with shovels. Trowels, brushes and a flexible baby bottle for blowing were employed when features or artifacts _in situ_ were encountered. The location of the screening dump was determined by test augering of the area between the site and the creek. This dump was separated from the excavation by a catwalk and low earthworks. The latter served the dual purpose of guarding against sliding from the dumps, and keeping out water which often poured over the edge of the overhang in the extremely rainy season of 1957.

Artifacts were sacked and later marked by level and square. Floral remains were similarly treated. Faunal material was rather sparse, and was therefore segregated by twelve inch levels measured from the datum point. All features were recorded and located on the map by means of a transit, and located vertically by measurements from the baseline.

Preliminary Discussion of the Stratigraphy